The present invention relates to improvements in apparatus for making packets or pods containing metered quantities of flowable solid material, particularly ground coffee, between two webs at least one of which contains liquid-permeable material. More particularly, the invention relates to improvements in making a strip of coherent packets or pods each of which contains a batch of a metered quantity of flowable solid material between two webs which are bonded together around the batches, e.g., in response to the application of heat and/or pressure. Such strips are often used in certain automatic beverage dispensing machines.
U.S. Pat. Nos. 3,186,137 and 3,293,042 to Eitzen disclose apparatus for making coherent packets which contain batches of ground coffee. The patented apparatus employ two discrete endless closed-link link chains which are mounted in and are movable in vertical planes. Each chain includes a number of plates which serve as supports for a first web of water-permeable material which, in turn, supports batches of ground coffee. The batches are thereupon compacted prior to being overlapped by a second web which is bonded to the first web around each condensed batch. The batches are normally flat disc-shaped accumulations of ground coffee and form a row in the resulting strip of coherent packets. Suitable means are provided for feeding the first web, the batches and the second web. A drawback of these patented apparatus is that the dimensions and weights of successively formed packets can fluctuate within a rather wide range and also that the batches are not compacted, or are not likely to be compacted, to the same extent.
U.S. Pat. No. 3,186,139 to Claus discloses a modified apparatus which also employs a closed-link chain moving in a horizontal plane and having a series of pairwise arranged plates. The lower plate of each pair has a recess serving to receive one-half of a batch of ground coffee particles. The upper plate of each pair is connected to the respective lower plate by a hinge and has an opening for the passage of various tools which are mounted on a mobile carrier and admit the batches and thereupon treat the batches prior to bonding of the two webs to one another. The lower plates of neighboring pairs of plates are articulately connected to each other by hinges extending transversely of the chain and the latter has an elongated upper run extending along several stations at which the conversion of the two webs and of batches of ground coffee into a succession of coherent packets takes place. The first web is acted upon by a shaping or molding tool which makes in its upper side a shallow pocket for the reception of one-half of a batch, the batches are thereupon compressed, the upper web is applied over the lower web and over the compressed batches, the two webs are bonded to each other around each compressed batch, and the thus obtained strip is perforated along one of its marginal portions.
The just described patented apparatus exhibits the drawback that the metering of batches is not entirely satisfactory. Moreover, if the compacting does not result in conversion of the entire batch into a cake of coherent particles of ground coffee, loose particles are likely to accumulate at the exterior of the second web to detract from the appearance of the packets and to interfere with the bonding of the webs to one another. Still further, the patented apparatus is bulky and its output is relatively low since a certain portion of each cycle or certain intervals between successive cycles, must be devoted to cleaning. Last but not least, the operation of the mobile carrier for the tools is not satisfactory because the carrier is not adequately guided for movement toward and away from various processing stations.